For Young's double slit experiment, two statements are given below: Statement I: If screen is moved away from the plane of slits, angular separation of the fringes remains constant. Statement II: If the monochromatic source is replaced by another monochromatic source of larger wavelength, the angular separation of fringes decreases. In the light of the above statements, choose the correct answer from the options given below:

A Statement I is false but Statement II is true

B Both Statement I and Statement II is true

C Both Statement I and Statement II are true

D Statement I is true but Statement II are false

The answer is D.

Solution

$\Delta\theta=\frac{\lambda}{d}$ depends on $\lambda$ but not on the screen distance.

$\Delta\theta=\frac{\lambda}{d}$ $\Delta\theta$ is proportional to $\lambda$ but independent of $D$.

Concept angular fringe separation

8 questions from this chapter have appeared across 8 exam years.